OK, it wasn't quite as simple as that. I had to get special government clearance, go through a security checkpoint that was a full five miles away from the supercomputer, and then get briefed on how to behave around Jaguar ("just don't touch anything").

Fully briefed and slightly intimidated, I was lead into a room roughly the size of a football field that houses the supercomputer, which itself is the size of a basketball court. For those who don't follow sports: it's really big.

It's also incredibly loud. Like, jet-engine loud. Even with ear-protection, my head was buzzing a little when I left the room.

The noise comes from the cooling fans that are located below the floor and atop the computer, which are required to literally keep the computer from melting. If you've ever noticed your laptop getting a little hot when it's sitting on your lap, multiply that by about 180,000 and you'll get an idea of why all that cooling is necessary.

The fans blow air up from the ground that has been chilled down to 60 degrees Fahrenheit, using 4,800 lbs. of R134 coolant -- the same stuff that cools your refrigerator and car air conditioner. When the air comes out the top of Jaguar, it's 120 degrees.

Also in the room are are Kraken, the 11th fastest supercomputer, and Gaea, the 52nd fastest, according to the biannual Top 500 supercomputer list, which was announced Monday. All three are used by different groups: Jaguar is a Department of Energy supercomputer, Kraken is used by the University of Tennessee, and Gaea is the supercomputer for the National Oceanic and Atmospheric Administration.

Their presence add to the room's noise and also creates a need for more storage space. That's why half the room is taken up by the 20,000 1-terabyte hard drives that store all the data that the massive computers churn out.

It's a lot of equipment, and there are the appropriate number of blinking LED lights emanating from all of the various components.

Meanwhile, computer engineers from Cray, the supercomputers' manufacturer, are running around wearing blue lab coats performing maintenance. Just like on your home PC, stuff is breaking or failing all the time on Jaguar, so on-site engineers are constantly checking up on the eight rows of 284 cabinets that make up the computer.

They're also working on a giant upgrade. Right now, Jaguar runs at 2 petaflops, which translates to 2 quadrillion (that's 2 million billion) calculations per second. That's fast, but the world's fastest supercomputer blows Jaguar away: Japan's K Computer runs at more than 10 petaflops.

Clearly, Jaguar is falling behind and needs more oomph. So the DOE decided to replace Jaguar's processors and turn it into a 20 petaflop machine -- twice as fast as K Computer. When the upgrade is finished in late 2012, the supercomputer will be appropriately renamed Titan, as it will likely be the world's fastest.

I was particularly fascinated by how Jaguar handles input and output. The computer runs a stripped-down version of Linux, the open-source operating system that powers most Web servers. Data and commands are entered into computer terminals similar to a PC interface, with keyboards and flat-screen monitors.

Output is where it gets really interesting. After data is spat out into spreadsheets, on-site imaging specialists transform that into stunning high-definition visualizations that can be viewed in a room one flight up from Jaguar. The viewing room has 27 high-definition projectors working in tandem to create wide-screen HD images of whatever the scientists cooked up using the supercomputer.

So messing around with a supercomputer is kind of like playing with your PC, except everything is many orders of magnitude bigger, faster, louder, brighter, and much, much more expensive.